EFFECTS OF NITROGEN ION-IMPLANTATION ON TRIBOLOGICAL PROPERTIES OF METALLIC SURFACES

The subject of the present work is the effects of nitrogen ion implantation on mechanical properties of metallic surfaces commonly encountered in machine building, such as electroplated hard chromium, sacrificial phosphate coating on cast iron, and plasma-face-coated hard molybdenum. A unique aspect of the work is that standard production samples, with no special surface preparation prior to the treatment, were investigated. This makes the present results immediately relevant in a production environment. In the parameter range explored, the treatment resulted in up to 31% wear reduction and 7% friction coefficient reduction for the chromium surface, up to 24% wear reduction and 13% friction coefficient reduction for the phosphate coating, and up to 90% wear reduction (to a tenth of the original value) and 84% surface hardness increase for the molybdenum deposit. The mechanisms responsible for the observed effects are discussed in detail. Trends in dependences on ion dose and energy permit extrapolation of the obtained data. These results demonstrate the applicability of ion implantation to unprepared metallic surfaces, and its readiness for immediate practical use.